Capacitive position sensor

ABSTRACT

Methods and apparatus related to a sensor are discussed herein. The sensor can include a sensing element having a sensing path, the sensing element coupled to a sensing channel, and a processor configured to interpret a signal generated by the sensing channel indicative of a capacitance between the sensing path and a system ground. The processor can have a first mode configured to set a parameter to a desired value. The desired value can be related to a first position of an object sensed along the sensing path and a range of parameter values mapped to a length of the sensing path. A second mode can adjust the parameter based on a displacement of the object along the sensing path.

RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.11/868,566, filed on Oct. 8, 2007, which claims the benefit of U.S.Provisional Application Ser. No. 60/862,358, filed Oct. 20, 2006, whichare incorporated herein by reference in their entirety.

BACKGROUND OF THE INVENTION

The invention, relates to capacitive position sensors, more particularlythe invention relates to capacitive position sensors for detecting theposition of an object around a curved path.

Capacitive position sensors are applicable to human interfaces as wellas material displacement sensing in conjunction with controls andappliances, mechanisms and machinery, and computing.

Capacitive position sensors in general have recently become increasinglycommon and accepted in human interfaces and for machine control. In thefield of home appliances, it is now quite common to find capacitivetouch controls operable through glass or plastic panels. These sensorsare increasingly typified by U.S. Pat. No. 6,452,514 which describes amatrix sensor approach employing charge-transfer principles. Electricalappliances, such as TV's, washing machines, and cooking ovensincreasingly have capacitive sensor controls for adjusting variousparameters, for example volume, time and temperature.

Due to increasing market demand for capacitive touch controls, there isan increased need for lower cost-per-function as well as greaterflexibility in usage and configuration. There exists a substantialdemand for new human interface technologies which can, at the rightprice, overcome the technical deficits of electromechanical controls onthe one hand, and the cost of touch screens or other exotica on theother.

EP1273851A2 discloses a device for adjusting temperature settings, powersettings or other parameters of a cooking apparatus. The devicecomprises a strip sensor which may be linear, curved or circular and maybe a capacitive touch sensor or some other form of touch sensor. Alinear display is arranged in parallel to the sensor. The capacitivetouch sensor is sensitive to the touch of a finger and the display stripis made up of multiple display segments which illuminate to show thecurrent touch setting as defined by a finger touch on the capacitivetouch sensor. A predetermined calibration curve relating to a parameterto be adjusted is mapped onto the strip, the range extending from aminimum value to a maximum value. The minimum value may correspond to anoff condition of the domestic appliance. Additional operational modesmay be associated with the adjustment strip to ascribe new functions tothe sensor strip. These can be selected by touching the display for acertain time. For example, a first additional mode can be entered bytouching for 5 seconds, and a second additional mode by touching for 10seconds. One of the additional operational modes is a zoom mode whichprovides for fine adjustment of the parameter value. The zoomoperational mode can be activated by a contact time of, for example, 10seconds. In the zoom mode an additional digital display is activated toshow the current numerical value of the parameter being adjusted. In thezoom mode, only a fraction (e.g. 10%) of the original adjustment rangeis mapped onto the adjustment strip so that moving a finger across thefull length of the sensor strip from left to right (or right to left)will only increase (decrease) the current setting of the parametervalue, thereby providing a finer adjustment. During this fineadjustment, the display strip keeps its original function as a relativeindicator of the full range between the minimum and maximum values.

More generally, linear, curved and circular sensor strips for adjustingcooker settings have been known for many years, for example see U.S.Pat. No. 4,121,204 (resistive or capacitive sensor), DE19645907A1(capacitive sensor), DE19903300A1 (resistive sensor), and EP1602882A1(optical sensor).

WO2006/133976A1, WO2007/006624A1 and WO2007/023067A 1 are more recentexamples of work on touch-sensitive control strips for domesticappliances using capacitive sensors. These three patent applicationswere filed before the priority date of the present application, butfirst published after the priority date of the present application. Inparticular, WO2006/133976A1 and WO2007/023067A1 disclose sensors with azoom function similar to the above-described EP1273851A2 which is usedfor setting a timer.

WO2006/133976A1 provides an adjustment strip with two operational modes.In the first mode the full parameter value range is mapped across thesensor strip. For example 0 to 99 minutes in a timer function. If a userwishes to set the timer to 30 minutes, he touches the stripapproximately one third way along. A parameter value of say 34 minutesis sensed by the capacitive sensor, and displayed to the user on anumeric display. Once the initial value has been set, the effect oftouching the sensor field is automatically changed to a second mode inwhich the parameter value is decreased (or increased) finely from theinitially selected value by an amount that depends on the distance movedby the finger along the sensor strip. In the example, the user can thenslide his finger from right to left to reduce the time from 34 minutesto the desired 30 minutes, using the display for visual feedback. Inthis way, the user can initially make a rough selection of the desiredparameter value with a point and touch action, and then refine it to theexact value desired by a finger sliding action.

WO2007/023067A1 provides an adjustment strip with two operational modesthat switch between mapping the full parameter value range across thesensor strip and a partial range selected to show the sub-range ofparameter values between which the parameter is most often set by auser. The example of setting the timer on a cooker is given.

While a zoom function is useful, prior art implementations of the zoomfunction have limitations regarding the manner in which the transitionis effected from the full range mode to the zoom mode. In EP1273851A2,the user is made to wait for a certain time, 10 seconds in the specificexample, until the transition occurs. On the other hand, inWO2006/133976A1 the transition automatically occurs as soon as a valuefrom the full range is selected. Neither transition mode is ideal, theformer can be frustratingly slow for the user, and the latter automatictransition to fine adjustment is undesirable in the case that theinitial touch sets a value that is a considerable way off what isintended by the user.

SUMMARY OF THE INVENTION

The invention provides an improved capacitive position sensor for anelectrical appliance in which a desired parameter value can be moreefficiently and accurately selected.

According to one aspect of the present invention, there is provided acapacitive position sensor for detecting a position of an objectcomprising: a sensing element comprising a sensing path; at least oneterminal connected to the sensing element; at least one sensing channelconnected to the at least one terminal in which the sensing channel isoperable to generate a signal indicative of capacitance between theterminal and a system ground; means to determine a position of an objecton the sensing element; and means to further refine the position of theobject corresponding to a value in a parameter range of values.

More particularly, this aspect of the invention provides a capacitiveposition sensor for setting a parameter or function to a desired valuein a range of parameter or function values by determining the positionof an object on a capacitive position sensor, the capacitive positionsensor comprising: a sensing element comprising a sensing path; at leastone terminal connected to the sensing element; at least one sensingchannel connected to the at least one terminal in which the sensingchannel is operable to generate a signal indicative of capacitancebetween the terminal and a system ground; means to determine a positionof an object on the sensing element; means to further refine theposition of the object corresponding to a value in the range ofparameter or function values; and a processor operable to interpret andprocess the signal to determine the approximate position of an object onthe sensing path, the processor being configured to provide a first modeof the capacitive position sensor in which the range of parameter orfunction values is mapped onto the sensing path and in which theparameter or function can be set to approximately the desired value by atouch of the sensing path at a first point, and a second mode in whichdisplacement of an object on the sensing element adjusts the parameteror function from the value initially set in the first mode, wherein theprocessor is configured to switch from the first mode to the second moderesponsive to capacitive coupling caused by moving displacement of anobject along the sensing path in relation to the first point of touch.

According to another aspect of the present invention, there is provideda method for determining the position of an object on a capacitiveposition sensor as hereinbefore defined, the method comprising bringingan object into proximity with the sensing element so as to determine aposition of the object, initiating a change in mode of the sensor torespond to capacitive coupling caused by moving displacement of anobject on the sensor element, displacing an object on the sensingelement to select a value in a parameter range of values, and processingthe signal to determine the selected parameter value.

More particularly, this aspect of the invention provides a method forsetting a parameter or function to a desired value in a range ofparameter or function values by determining the position of an object ona capacitive position sensor, the capacitive position sensor comprising:a sensing element comprising a sensing path; at least one terminalconnected to the sensing element; at least one sensing channel connectedto the at least one terminal in which the sensing channel is operable togenerate a signal indicative of capacitance between the terminal and asystem ground; means to determine a position of an object on the sensingelement; and means to further refine the position of the objectcorresponding to a value in the range of parameter or function values,the method comprising: in a first mode of the capacitive position sensorin which the range of parameter or function values is mapped onto thesensing path bringing an object into proximity with the sensing elementat a first point so as to determine a position of the object and therebyinitially set the parameter or function to approximately the desiredvalue; initiating a change in mode of the sensor from the first mode toa second mode responsive to capacitive coupling caused by movingdisplacement of the object along the sensing path in relation to thefirst point of touch of the object on the sensing element; in the secondmode displacing the object on the sensing element to adjust theparameter or function from the value initially set to the desired value;and processing the signal to determine the selected parameter orfunction value.

In an embodiment of the invention, the capacitive sensor may work in afirst mode and a second mode. In a first mode, a signal may be generatedwhich is indicative of capacitive coupling of an object, for example auser's finger, with the sensing element. The signal generated in thefirst mode may provide an approximate position of an object in relationto a desired parameter value the user wishes to select. A processor maypreferably be provided to interpret and process the signal to determinethe approximate position of an object on the sensing element. It ispreferred that in the first mode of operation, the capacitive sensor maygenerate a signal indicative of capacitive coupling caused by bringingan object into proximity with a desired location on the sensor or bymoving displacement of the object in proximity with the sensing element.

In an embodiment of the invention, the capacitive sensor may enter asecond mode of operation if moving displacement of the object inproximity with the sensing element during a first mode of operationexceeds a minimum threshold value. For example, for a sensing element inthe form of a rotary capacitive sensor, if a user displaces an object inproximity with the sensing element during a first mode of operation by aminimum threshold angle in relation to a first point of touch of theobject on the sensing element, the capacitive sensor may switch into asecond mode of operation. The minimum threshold angle may be determinedby an algorithm programmed into a microcontroller and the thresholdangle may be set at different values depending on the sensitivityrequired and the parameter which is being adjusted. In one embodiment,the threshold angle may be set at 20 degrees before the capacitivesensor switches from the first mode to the second mode of operation. Anapproximate parameter value may be obtained in the first mode and in thesecond mode a desired parameter value may be selected.

In the second mode of operation, an object may be displaced in proximitywith the sensing element by a pre-determined threshold value, forexample 20 degrees, to effect an incremental change in the parametervalue thereby allowing a desired specific parameter value to beselected. Advantageously, a capacitive sensor of the invention operatingin a first mode may allow a parameter value to be selected (which may bethe desired value, or near to the desired value, the user wishes toselect) and in a second mode the sensor may effect an incrementalincrease or decrease of the parameter value selected in the first mode.In the second mode, a parameter value may be increased or decreased by apre-determined amount, for example ±1 unit, ±5 units, or ±10 units,based on the number of times an object is displaced on the sensingelement exceeding a pre-determined threshold value. Therefore, thethreshold value may correspond to an increase or decrease of theparameter value by, say, ±1 unit, and each time the threshold value isreached (n times) the parameter value will increase or decrease by ±1 (ntimes ±1).

In an alternative embodiment of the invention, the capacitive sensor mayenter a second mode of operation by effectively ‘zooming-in’ on anarrower range of parameter values, compared to the parameter rangedisplayed in the first mode, so that a user may accurately select adesired parameter value. The narrower range of parameter values shownduring the second mode will be determined by the parameter valueselected in the first mode, for example plus and minus 10 units from thevalue selected in the first mode. In the second mode of operation, anobject may be displaced along the sensing element so as to select thedesired parameter value.

Preferably the processor for determining the position of an object inproximity with the sensing element in a first mode of operation may beoperable for also determining the position of an object in proximitywith the sensing element in a second mode of operation.

Therefore, in the invention the capacitive sensor may function in afirst mode of operation in which an approximate parameter value may beselected followed by a second mode of operation in which a specificparameter value may be selected. The range of parameter valuesassociated with the capacitive sensor (i.e. the resolution) maydetermine whether a desired parameter value can be selected in the firstmode of operation. The second mode of operation will allow a desiredparameter value to be accurately selected, for example, either byzooming-in on a narrower range of parameter values around the parametervalue selected in the first mode and displacing an object in proximitywith the sensing element to select the desired value, or, by displacingan object in proximity with the sensing element to exceed apredetermined threshold value in order to change the parameter valueselected from the first mode by one or more increments. The number oftimes the threshold value is exceeded may determine the number of timesthe parameter value is increased or decreased.

A capacitive sensor of the invention may be incorporated into a controlpanel of an electronic appliance or gadget, for example a cooking oven,microwave oven, television, washing machine, MP3 player, mobile phone,or other multimedia device. A wide range of parameters/functions may becontrolled by the capacitive sensor of the invention, dependent on thetype of electronic appliance in which the capacitive sensor isincorporated, for example, temperature, volume, contrast, brightness, orfrequency. The parameter or function to be controlled may be selectedprior to use of the capacitive sensor.

Advantageously, the sensor has a higher degree of resolution in thesecond mode allowing a user to move their finger in proximity with thesensing element to select a specific parameter value. If the sensingelement is in the form of a closed loop, a user may be able to scrollclockwise or anticlockwise around the sensing element to select thedesired value. In the second mode for example, a 20 degree rotation maybe equivalent to changing a parameter value by 1 unit. The amount ofrotation required by an object on the sensing element to cause anincremental change in a parameter value may be varied dependent on theparameter or function being controlled. Control circuitry or aprogram-controlled microprocessor may be used to control the degree ofrotation required to cause a change in a parameter value.

In a preferred embodiment of the invention, the sensing element isarcuate in shape. It is particularly preferred that the sensing elementis in the form of a closed loop for use in a rotary capacitive positionsensor. In a rotary capacitive position sensor embodiment, an object maybe moved along the sensing element of the sensor for a plurality ofrevolutions and the distance moved by the object may determine theoutput signal which is generated by the sensing channel(s).

In the first mode of operation of the capacitive sensor, capacitivecoupling of an object in proximity with a sensing element may bedetected to give an approximate position in relation to a range ofvalues for a given parameter. If a user wishes to obtain differentposition data, the object may be removed from proximity with the sensingelement and then brought into proximity with the said sensing elementagain. In other words, a user may initiate the first mode of the sensoragain simply by retouching the sensing element. When the second mode ofoperation is initiated, a user may scroll the sensing element to selecta specific value of a certain parameter. An output signal may begenerated indicative of a specific parameter value when an object ceasesdisplacement at a certain position on the sensing element. In anembodiment, if a user releases touch from the sensing element in asecond mode and retouches the sensing element then the first mode ofoperation may be activated again.

In an embodiment of the invention, the capacitive position sensor mayfurther comprise one or more discrete sensing areas in the centre regionof a rotary sensing element. Preferably, if the sensing areas in thecentre region of the sensing element sense capacitive coupling to anobject, any signal produced from the sensing element is reduced or‘locked out’ using the Adjacent Key Suppression™ technology described inthe applicant's earlier U.S. Pat. No. 6,993,607 and U.S. Ser. No.11/279,402 both incorporated herein by reference. Any output signal fromthe rotary sensing element caused by capacitive coupling with an objectmay also lock out a signal from the central sensing areas. The sensingelement may be embodied by a single resistor, for example it maycomprise a resistive material deposited on a substrate to form acontinuous pattern. This provides for an easy-to-fabricate resistivesensing element which can be deposited on the substrate in any one of arange of patterns. Alternatively, the sensing element may be made from aplurality of discrete resistors. The discrete resistors may bealternately connected in series with a plurality of conducting senseplates, the sense plates providing for increased capacitive couplingbetween the object and the resistive sensing element. This provides fora resistive sensing element which can be fabricated from widelyavailable off-the-shelf items. The disclosure of WO2005/019766 isincorporated herein by reference as an example of the capacitancemeasurement circuitry which may be used. Alternatively, a resistor-lesssensing element similar to that described in U.S. Pat. No. 4,264,903 maybe used to form the capacitive sensor of the invention.

The resistive sensing element may have a substantially constantresistance per unit length. This provides for a capacitive positionsensor having a simple uniform response. Where greater positionalresolution is required and/or when employing a relatively long resistivesensing element, the resistive sensing element may include a pluralityof terminals.

The object to be detected may be a pointer, for example a finger or astylus, which can be freely positioned by a user. Alternatively, theobject may be a wiper held in proximity to the resistive sensingelement, the position of the wiper along the resistive sensing elementbeing detected by the capacitive position sensor. The position of thewiper may be adjusted by a user, for example by turning a rotary knob,or may be coupled to a shaft driven by connected equipment such that thecapacitive position sensor can act as an encoder.

Further objects of some embodiments of the invention are to provide fora sensor having high reliability, a sealed surface, low powerconsumption, simple design, ease of fabrication, and the ability tooperate using off-the-shelf logic or microcontrollers.

In U.S. Pat. No. 6,466,036, the applicant teaches a capacitive fieldsensor employing a single coupling plate to detect change in capacitanceto ground. This apparatus comprises a circuit employing repetitivecharge-then-transfer or charge-plus-transfer cycles using commonintegrated CMOS push-pull driver circuitry. This technology forms thebasis of some embodiments of the invention and is incorporated byreference herein.

Some definitions are now made. ‘Element’ refers to the physicalelectrical sensing element made of conductive substances. ‘Electrode’refers to one of the galvanic connection points made to the element toconnect it to suitable driver/sensor electronics. The terms ‘object’ and‘finger’ are used synonymously in reference to either an inanimateobject such as a wiper or pointer or stylus, or alternatively a humanfinger or other appendage, any of whose presence adjacent the elementwill create a localized capacitive coupling from a region of the elementback to a circuit reference via any circuitous path, whethergalvanically or non-galvanically. The term ‘touch’ includes eitherphysical contact between an object and the element, or, proximity infree space between object and element, or physical contact betweenobject and a dielectric (such as glass) existing between object andelement, or, proximity in free space including an intervening layer ofdielectric existing between object and element. Hereinafter the terms‘circle’ or ‘circular’ refer to any ellipsoid, trapezoid, or otherclosed loop of arbitrary size and outline shape having an open middlesection.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described by way of example only withreference to the embodiments described and shown in the drawings.

FIG. 1 shows a control panel of an apparatus embodying a rotarycapacitive sensor, the sensor being used in a first mode of operation.

FIG. 2 a shows the capacitive sensor of FIG. 1 being used by in a secondmode of operation, with the user scrolling around the sensor in ananti-clockwise direction.

FIG. 2 b shows the capacitive sensor of FIG. 1 being used in a secondmode of operation, with the user scrolling around the sensor in aclockwise direction.

FIG. 3 shows a control panel of an apparatus according to anotherembodiment, in which a rotary capacitive sensor is being used in a firstmode of operation.

FIG. 4 shows the capacitive sensor of FIG. 3 being used in a second modeof operation.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 illustrates part of a control panel 50 having a capacitive sensor60 and a digital readout display 70. The control panel 50 may beincorporated into an electronic appliance such as a cooking oven,microwave oven, washing machine, fridge freezer, television, MP3 player,mobile telephone or the like. The parameter or function to be controlledby the capacitive sensor will depend on the type of electrical appliancein which the capacitive sensor is incorporated. Parameters like volume,temperature, operating program, brightness, contrast are some examplesof functions that may be controlled by the capacitive sensor of theinvention. In a preferred embodiment of the invention, the parameter tobe controlled may be chosen from a predetermined list of parameters sothat a user may advantageously adjust different parameters on anelectrical appliance or apparatus. The capacitive sensor 60 shown inFIG. 1 is set to control cooking temperature of a microwave or cookingoven.

The capacitive sensor 60 comprises a rotary sensing element 100 fordetecting capacitive coupling with an object, typically an operator'sfinger. A Liquid Crystal Display 75 (or other known display) is formedin the control panel 50 to illuminate the temperature scale around thesensing element. The temperature scale ranges from 0 to 300 degreesCentigrade. The capacitive sensor 60 is shown in a first mode ofoperation in which a user's finger is used to select a cookingtemperature. A user's finger 80 is shown in proximity with a portion ofthe sensing element 100 corresponding to a temperature of 175 degreesCentigrade (° C.) which is displayed on the digital readout display 70.The selected temperature of 175° C. may be the desired temperaturerequired by the user, but in most cases the temperature selected in thefirst mode of operation will indicate a temperature near to the actualtemperature required by the user. A user may re-touch the sensingelement 100 of the sensor to reactivate the first mode of operation andselect a different temperature. The resolution of the sensor maydetermine how close the temperature selected in the first mode is to thedesired temperature sought by the user.

Turning now to FIGS. 2A and 2B, the capacitive sensor 60 is shown in asecond mode of operation. The capacitive sensor automatically enters thesecond mode of operation after a temperature has been selected in thefirst mode of operation. In the second mode, a user is able to increaseor decrease the temperature selected in the first mode by apre-determined increment. Changing the temperature by a given incrementdepends on a user displacing their finger in proximity with the sensingelement 100 by a pre-determined threshold angle. The embodiment shown inFIGS. 2A and 2B requires a 20° rotation (i.e. threshold angle is 20°) toeffect a temperature change of ±1° C.

As shown in FIG. 2A, a user has displaced their finger in proximity withthe sensing element 100 in an anti-clockwise direction to decrease thetemperature of 175° C. selected in the first mode. The user has movedhis finger by 40° (i.e. 2× the threshold angle) from the first point oftouch in the first mode of operation, to cause a temperature decrease by2° C. to 173° C. (shown by arrow C). As shown in FIG. 2B, the user hasmoved his finger by 40° in a clockwise direction from the first point oftouch in the first mode of operation, to cause a temperature increase by2° C. to 177° C. (arrow D). Advantageously, the capacitive sensor in thesecond mode of operation allows a user to accurately select a desiredtemperature. The resolution of the capacitive sensor in the second modeof operation is typically finer than that in the first mode ofoperation. The threshold angle may be re-settable and is typicallydetermined by a program stored in a microcontroller.

In the second mode of operation as illustrated in FIGS. 2A and 2B, a +and − indicator display 92 is present above the capacitive sensor 60 toindicate to the user that the temperature can be increased or decreasedby 1 unit(s). The digital display 70 shows the temperature as it ischanged by the user. The LCD 75 showing the temperature scale in thefirst mode is no longer highlighted during the second mode of operation.

FIG. 3 illustrates a rotary sensing element 20 of a capacitive positionsensor 10 embodying the invention. The capacitive sensor 10 isincorporated into a control panel of a cooking oven. The capacitivesensor 10 shown in FIG. 1 is used to select a desired cookingtemperature, although the sensor could be used for selecting anyparticular parameter value based on the electrical appliance in use. Thesensor of FIG. 1 is shown in a first mode of operation. A user's finger30 approaches the rotary sensing element 20 and is capacitively coupledto the sensing element in the region between 150 to 200° C. Atemperature of 175° (is shown in the digital display 70. The first modeof operation of the sensor allows the user to select an approximatecooking temperature. The rotary sensing element 20 may have a diameterof about 2 inches which, prior to the invention, may make it difficultfor a user to accurately select a certain temperature.

The capacitive sensor 10 automatically enters a second mode of operationafter a temperature has been selected in the first mode, as illustratedin FIG. 4. As shown in FIG. 4, the temperature scale around the sensingelement 20 has been modified or reset to expand the temperature range inthe capacitively coupled region determined from the first mode ofoperation. The user may now select a desired temperature for cooking byscrolling his finger clockwise or anticlockwise around the sensingelement until the desired temperature is reached, in this case 180° C.as shown on the digital display 70. The temperature scale illustrated inFIG. 4 is only an example of how the capacitive sensor may be programmedto zoom in on a pre-determined temperature range. In the second mode ofoperation, the number of degrees of rotation required to effect atemperature change by a certain increment may be adjusted. Thetemperature selected may be displayed on an analogue or digital readoutdisplay formed within the control panel, such as on digital display 70.

Although the present invention has been described with respect topreferred embodiments, many modifications and alterations can be madewithout departing from the invention. Accordingly, it is intended thatall such modifications and alterations be considered as within thespirit and scope of the invention.

1. A sensor comprising: a sensing element comprising a sensing pathhaving a length; at least one sensing channel coupled to the sensingelement, the sensing channel operable to generate a signal indicative ofcapacitance between the sensing path and a system ground; a processorhaving a first mode and a second mode, the processor configured todetermine a first position of an object along the sensing path using thesignal and to set a parameter to an initial value in the first mode,wherein the initial value is related to the first position along thesensing path and to a range of parameter values associated with thelength of the sensing path, the processor further configured to adjustthe parameter in a second mode in response to a displacement of theobject along the sensing path from the first position, wherein theprocessor is configured to switch from the first mode to the second modewhen the signal indicates displacement of the object, proximate thesensing element, along the sensing path.
 2. The sensor of claim 1,wherein the sensing path is formed as a closed loop.
 3. The sensor ofclaim 1, wherein the processor is configured to change from the firstmode to the second mode when the displacement of the object exceeds aminimum threshold displacement.
 4. The sensor of claim 3, wherein theminimum threshold value is predetermined and the processor isconfigurable to set the minimum threshold value at different valuesdepending on a sensitivity setting and the parameter.
 5. The sensor ofclaim 1, wherein, in the second mode, the processor effects anincremental change in the parameter value when it is sensed that theobject has moved along the sensing path by a pre-determined thresholddisplacement.
 6. The sensor of claim 1, wherein, in the second mode, theprocessor changes the parameter value by a number of units based on thenumber of times the displacement of the object along the sensing path issensed to have exceeded the pre-determined threshold displacement. 7.The sensor of claim 1, wherein, in the second mode, the processor maps anarrower sub-range of parameter values onto the sensing path around theinitial value set in the first mode.
 8. The sensor of claim 1, whereinthe processor is further configured such that if a release of touch fromthe sensing element in the second mode followed by a subsequentre-touching of the sensing element is sensed, then the first mode isactivated.
 9. The sensor of claim 1, wherein the parameter set using thecapacitive position sensor is selected from the group consisting oftemperature, volume, contrast, brightness, and frequency.
 10. The sensorof claim 1, wherein the processor is configured to allow selection ofthe parameter prior to use of the capacitive position sensor.
 11. Acontrol panel of an electronic appliance incorporating a capacitiveposition sensor according to claim
 1. 12. An electronic appliance havinga control panel incorporating a capacitive position sensor according toclaim
 1. 13. The electronic appliance of claim 12 selected from thegroup consisting of a cooking oven, microwave oven, television, washingmachine, MP3 player, mobile phone, and multimedia device.
 14. A methodcomprising: detecting an object proximate a first position along asensing path of a capacitive position sensor; activating a first mode ofthe capacitive position sensor; setting a parameter to an initial valuerelated to the first position; sensing a displacement of the object fromthe first position, the object proximate a sensing element along thesensing path of the capacitive position sensor; initiating a change inmode of the sensor from the first mode to a second mode using the senseddisplacement of the object along the sensing path; and incrementallyadjusting the parameter from the initial value using a magnitude of thedisplacement.
 15. The method of claim 14, including mapping a range ofvalues along a length of the sensing path.
 16. The method of claim 14,wherein the sensing path is formed as a closed loop.
 17. The method ofclaim 14 wherein the sensing a displacement includes sensing adisplacement having a magnitude that exceeds a minimum thresholddisplacement in order to initiate a change in mode of the sensor fromthe first mode to the second mode.
 18. The method of claim 17, includingsetting a minimum threshold displacement using a sensitivity setting andthe parameter.
 19. The method of claim 14, wherein the incrementallyadjusting the parameter includes incrementally adjusting the parameterafter sensing the object has moved along the sensing path by a minimumthreshold displacement.
 20. The method of claim 14, wherein theincrementally adjusting the parameter includes incrementally adjustingthe parameter by a number of units based on the number of times thedisplacement of the object along the sensing path exceeds a minimumthreshold displacement.
 21. The method of claim 14, including mapping anarrower sub-range of parameter values onto the sensing path in thesecond mode, wherein the narrower sub-range of parameter values includesthe initial value set in the first mode.
 22. The method of claim 14,including switching from the second mode to the first mode upon sensingthe first position of the object.
 23. The method of claim 14, includingreceiving information to select the parameter from the group consistingof temperature, volume, contrast, brightness, and frequency.
 24. Themethod of claim 23, wherein the receiving information to select theparameter includes receiving information to select the parameter priorto use of the capacitive position sensor.